In the hard-boiled narration describing the gnarly nighttime world of Sin City, people are constantly talking about how rough it is and how lethal the people are. They left out one thing: You could also die of boredom here.

Or so it seems in “Sin City: A Dame to Kill For,” a sequel to the imaginative 2005 film. With its all-digital black-and-white world and retro-film-noir mood no longer a novelty, the second film comes up short in inspiration and originality.

A batch of characters return from the first installment. One is Marv, the granite-faced strongman who idealizes a stripper named Nancy (Jessica Alba, also returning). Marv is played by Mickey Rourke, whose appearance has been freakishly altered by make-up and digital sculpting.

We also re-encounter a crooked politician (Powers Boothe), a tough street chick (Rosario Dawson), and a cop — or his ghost, I guess — played by Bruce Willis.

The stories collide, but for the long middle section of the movie we follow the ape-like Dwight (Josh Brolin), a none-too-bright private eye tormented by a green-eyed vixen named Ava (Eva Green, late of “300: Rise of an Empire” and TV’s “Penny Dreadful”). This plot line takes place before the events of the first “Sin City” movie, although the Marv/Nancy story takes place after that film. Good luck with that.

There’s also a particularly mystifying thread about a gambler (Joseph Gordon-Levitt) who challenges the corrupt politician to repeated games of poker. Like much in the Sin City world, this one is awash in revenge fantasies, ultra-violence, and images of women as either duplicitous hookers or innocents needing to be saved.

The stories are drawn from Frank Miller’s graphic novels, and once again Miller co-directs the film with Robert Rodriguez. The movie’s got some snazzy 3D images (the actors play their roles in front of green screens and the detail is filled in later), but the stories themselves are flabby.

Gordon-Levitt and the bounteously displayed Eva Green are the only performers with zip. Green’s story could be described as a parody of adolescent misogynistic fantasies, but the movie’s grasp of humor is so uncertain I think it’s meant to be taken straight.

The brutality from the first “Sin City” is intact, but this one’s shorter. It only feels longer. The fantasy world of Sin City is supposed to be full of sentimentally tough guys and dames, but really these characters just seem exceptionally dumb. That’s a recipe for tedium, as “A Dame to Kill For” proves.

“Sin City: A Dame to Kill For” (1½ stars)

Sequel to the 2005 film by Frank Miller and Robert Rodriguez. Without the novelty of that film’s digital, graphic-novel approach, this one collapses in tedium. A mix of stories conjure up the corrupt world of Sin City, a film noir place where the people are supposed to be sentimentally tough guys and dames but really just seem dumb. With Mickey Rourke, Josh Brolin, Eva Green.

Rating: R, for violence, nudity, language

Showing: Alderwood Mall, Cinebarre Mountlake Terrace, Edmonds Theater, Galaxy Monroe, Marysville, Meridian, Sundance Cinemas Seattle, Thornton Place Stadium 14, Woodinville, Cascade Mall.